hi ya leif
yupp... marketing hipe ... that the "set of machines/cluster"
will provide 99.999% uptime ... not invididually
an individual machine going down for normal maintenance
or emergency failure is NOT counted in teh overal 5-nine's uptime
its practically impossible for one machine to provide
99.999% uptime...
- my best machines been up over 800 days... non-stop
but still went down (init 1 )for e2fsck once in a while
and backup ....( uptime remains un-interrupted )
- uptime can be faked :-)
- uptime is interrupted by reset and power off
and is oblibious to "init 1" to do maintanence
- so what is the definition of 99.999% uptime ???
- marketing voo-doo :-)
- if an indiviual PC goes down ( any reason ) it should
be included in the 99.999 reliability/uptime
( it costs time and $$$ to play with each PC )
c ya
alvin
#
# remember that a pc takes about a minute-or-two to power down
# and slightly longer to reboot -- lost couple minutes already
#
http://www.Linux-Consulting.com/HA/99.999.txt
15minutes/day downtime ----> 99.0278% -- good enough for most --
15minutes/week downtime ---> 99.8611%
15minutes/month downtime --> 99.9676%
15minutes/quarter downtime-> 99.9892%
15minutes/year downtime ---> 99.9973%
15minutes/4 years downtime-> 99.9993% <<< ahh finally >>
-- your machine cannot go down for more than 15 minutes
over a 4 year period :-)
On 6 Nov 2002, Leif Nixon wrote:
>> So a single node failure doesn't count against the uptime, is that
> what you are saying? If that is the case, precisly what definition of
> "uptime" are you using?
>